Cognitive effects of transcranial direct current stimulation combined with working memory training in fibromyalgia: a randomized clinical trial

Cognitive dysfunction in fibromyalgia has been reported, especially memory. Anodal transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) has been effective in enhancing this function. We tested the effects of eight sessions of tDCS and cognitive training on immediate and delayed memory, verbal fluency and working memory and its association with brain-derived neurotrophic factor (BDNF) levels. Forty females with fibromyalgia were randomized to receive eight sessions of active or sham tDCS. Anodal stimulation (2 mA) was applied over the DLPFC and online combined with a working memory training (WMT) for 20 minutes. Pre and post-treatment neurocognitive tests were administered. Data analysis on deltas considering years of education and BDNF as covariates, indicated active-tDCS + WMT significantly increased immediate memory indexed by Rey Auditory Verbal Learning Test score when compared to sham. This effect was dependent on basal BDNF levels. In addition, the model showed active stimulation increased orthographic and semantic verbal fluency scores (Controlled Oral Word Association Test) and short-term memory (Forward Digit Span). The combination of both techniques seemed to produce effects on specific cognitive functions related to short-term and long-term episodic memory and executive functions, which has clinical relevance for top-down treatment approaches in FM.financiamento: This research was supported by grants and material support from the following Brazilian agencies: Committee for the Development of Higher Education Personnel - CAPES - PNPD/CAPES and material support. National Council for Scientific and Technological Development - CNPq (grants to Dr. I.L.S. Torres, Dr. W. Caumo). Postgraduate Program in Medical Sciences at the School of Medicine of the Federal University of Rio Grande do Sul (material support). Postgraduate Research Group at the Hospital de Clinicas de Porto Alegre - FIPE HCPA (material support). Foundations for Support of Research at Rio Grande do Sul (FAPERGS) (material support)

Slower is not always better: Response-time evidence clarifies the limited role of miserly information processing in the Cognitive Reflection Test

We report a study examining the role of `cognitive miserliness' as a determinant of poor performance on the standard three-item Cognitive Reflection Test (CRT). The cognitive miserliness hypothesis proposes that people often respond incorrectly on CRT items because of an unwillingness to go beyond default, heuristic processing and invest time and effort in analytic, reflective processing. Our analysis (N = 391) focused on people's response times to CRT items to determine whether predicted associations are evident between miserly thinking and the generation of incorrect, intuitive answers. Evidence indicated only a weak correlation between CRT response times and accuracy. Item-level analyses also failed to demonstrate predicted response time differences between correct analytic and incorrect intuitive answers for two of the three CRT items. We question whether participants who give incorrect intuitive answers on the CRT can legitimately be termed cognitive misers and whether the three CRT items measure the same general construct

Effect of response format on cognitive reflection: Validating a two- and four-option multiple choice question version of the Cognitive Reflection Test

The Cognitive Reflection Test, measuring intuition inhibition and cognitive reflection, has become extremely popular since it reliably predicts reasoning performance, decision-making and beliefs. Across studies, the response format of CRT items sometimes differs, assuming construct equivalence of the tests with open-ended vs. multiple choice items (the equivalence hypothesis). Evidence and theoretical reasons, however, suggest that the cognitive processes measured by these response formats and their associated performances might differ (the non-equivalence hypothesis). We tested the two hypotheses experimentally by assessing the performance in tests with different response formats and by comparing their predictive and construct validity. In a between-subjects experiment (n = 452), participants answered an open-ended, a two- or a four-option response format of stem-equivalent CRT items and completed tasks on belief bias, denominator neglect and paranormal beliefs (benchmark indicators of predictive validity) as well as actively open-minded thinking and numeracy (benchmark indicators of construct validity). We found no significant differences between the three response formats in the number of correct responses, the number of intuitive responses (with the exception of the two-option version being higher than the other tests) and in the correlational patterns with the indicators of predictive and construct validity. All three test versions were similarly reliable but the multiple-choice formats were completed more quickly. We speculate that the specific nature of the CRT items helps to build construct equivalence among the different response formats. We recommend using the validated multiple-choice version of the CRT presented here, particularly the four-option CRT, for practical and methodological reasons

Electrical Brain Stimulation During a Retrieval-Based Learning Task Can Impair Long-Term Memory

Anodal transcranial direct current stimulation (tDCS) to the left dorsolateral prefrontal cortex (DLPFC) has been shown to improve performance on a multitude of cognitive tasks. These are, however, often simple tasks, testing only one cognitive domain at a time. Therefore, the efficacy of brain stimulation for complex tasks has yet to be understood. Using a task designed to increase learning efficiency, this study investigates whether anodal tDCS over the left DLPFC can modulate both learning ability and subsequent long-term memory retention. Using a within-subject design, participants (N = 25) took part in 6 training sessions over consecutive days in which active or sham stimulation was administered randomly (3 of each). A computer-based task was used, containing flags from countries unknown to the participants. Each training session consisted of the repetition of 8 pairs of flag/country names. Subsequently, in three testing sessions, free, cued, and timed cued recall, participants were assessed on all 48 flags they had learnt. No difference in learning speed between active and sham tDCS was found. Furthermore, in the timed cued recall phase, flags learnt in the sham tDCS sessions were recalled significantly better than flags learnt in the active tDCS sessions. This effect was stronger in the second testing session. It was also found that for the flags answered incorrectly; thus, meaning they were presented more frequently, subsequent long-term retention was improved. These results suggest that for a complex task, anodal tDCS is ineffective at improving learning speed and potentially detrimental to long-term retention when employed during encoding. This serves to highlight the complex nature of brain stimulation, providing a greater understanding of its limitations and drawbacks

Targeting the human cerebellum with transcranial direct current stimulation to modulate behavior: A meta-analysis

Contains fulltext : 186876.pdf (publisher's version ) (Open Access)Transcranial direct current stimulation (tDCS) is increasingly used to study motor- and non-motor-related functions of the cerebellum. The aim of the present study was to quantitatively review available studies to estimate the efficacy of cerebellar tDCS in altering motor- and cognitive-related behavioral performance in healthy volunteers. The present meta-analysis included 32 sham-controlled studies. Results from random effects modeling of the cumulative effect size demonstrated that anodal and cathodal tDCS to the cerebellum were effective in changing performance. No evidence for polarity-dependent effects of cerebellar tDCS was found. Current findings establish the feasibility to target motor and non-motor-related cerebellar functions with tDCS, but arguably due to anatomical differences between the cerebellum and cerebral cortex, the polarity of tDCS is not predictive of the direction of the behavioral changes in healthy volunteers.9 p

Differential influence of the dorsal premotor and primary somatosensory cortex on corticospinal excitability during kinesthetic and visual motor imagery: A low-frequency repetitive transcranial magnetic stimulation study

Consistent evidence suggests that motor imagery involves the activation of several senso-rimotor areas also involved during action execution, including the dorsal premotor cortex (dPMC) and the primary somatosensory cortex (S1). However, it is still unclear whether their involvement is specific for either kinesthetic or visual imagery or whether they contribute to motor activation for both modalities. Although sensorial experience during motor imagery is often multimodal, identifying the modality exerting greater facilitation of the motor system may allow optimizing the functional outcomes of rehabilitation interventions. In a sample of healthy adults, we combined 1 Hz repetitive transcranial magnetic stimulation (rTMS) to suppress neural activity of the dPMC, S1, and primary motor cortex (M1) with single-pulse TMS over M1 for measuring cortico-spinal excitability (CSE) during kinesthetic and visual motor imagery of finger movements as compared to static imagery conditions. We found that rTMS over both dPMC and S1, but not over M1, modulates the muscle-specific facilitation of CSE during kinesthetic but not during visual motor imagery. Fur-thermore, dPMC rTMS suppressed the facilitation of CSE, whereas S1 rTMS boosted it. The results highlight the differential pattern of cortico-cortical connectivity within the sensorimotor system during the mental simulation of the kinesthetic and visual consequences of actions

Effectiveness of Computerized Cognitive Training Programs (CCTP) with Game-like Features in Children with or without Neuropsychological Disorders: a Meta-Analytic Investigation

Computerized cognitive training programs (CCTP) are based on the assumption that cognitive abilities may be boosted by repetitively performing challenging tasks. The integration of game-like features in these programs, associated with the goal of amusing or rewarding participants, may contribute to generate cognitive benefits. Indeed, reinforcement contingencies have been reported to produce positive effects on performance and motivation, especially in children. This meta-analysis was aimed at providing a quantitative summary of the effectiveness of CCTP with game-like features in school-aged children with typical and atypical development. A total of 24 studies, with the cognitive and behavioral outcome data of 1547 participants, were selected for inclusion in the meta-analysis. Subgroup analyses were performed to identify the sources of the observed methodological heterogeneity. A robust variance estimation model, after removal of study outliers, yielded a small-to-moderate significant effect size. Final results pointed out smaller but more precise estimate effect sizes according to methodological aspects related to cognitive domain of outcomes, standardization of measures and type of control applied. Alongside supporting the use of CCTP for rehabilitating cognitive functions, the present results shed light on how different methodological choices are able to shape research findings in the field of children\u2019s cognitive rehabilitation

TMS Over the Cerebellum Interferes with Short-term Memory of Visual Sequences

Growing evidence suggests that the cerebellum is not only involved in motor functions, but it significantly contributes to sensory and cognitive processing as well. In particular, it has been hypothesized that the cerebellum identifies recurrent serial events and recognizes their violations. Here we used transcranial magnetic stimulation (TMS) to shed light on the role of the cerebellum in short-term memory of visual sequences. In two experiments, we found that TMS over the right cerebellar hemisphere impaired participants' ability to recognize the correct order of appearance of geometrical stimuli varying in shape and/or size. In turn, cerebellar TMS did not affect recognition of highly familiar short sequences of letters or numbers. Overall, our data suggest that the cerebellum is involved in memorizing the order in which (concatenated) stimuli appear, this process being important for sequence learning

Glucocerebrosidase is imported into mitochondria and preserves complex I integrity and energy metabolism

GBA1 mutations cause Gaucher’s disease and are the strongest risk factor for Parkinson’s disease. Using stable cell lines and patient iPSCs, the authors show mitochondrial localization of GBA1, which may affect neurodegenerative disease risk